With every case from years ago there should be lessons learned.

The good news is that the international coalition, in which our military contributes, has done a lot to reduce the ground space, the territory in Iraq, Syria that ISIL once occupied a couple years ago. That's a good thing. And a lot of that, frankly, has occurred in Trump administration, so I'll give them credit for that.

I'll never forget what a Catholic priest told me; he said, "If you try to padlock the door, you have to give people an alternative path - an alternative, safer path. You can't padlock, and you shouldn't padlock a burning building."

I think that ISIS is a problem and it's really a symptom of a much greater problem.

I think that the potential for homegrown terrorist attacks is something that we have to be very concerned about, because, in many respects, it's harder to detect when you have an independent actor who may be living in our midst, in our own communities.

President Trump talks about extreme vetting, and we actually do have extreme vetting when it comes to refugee resettlement. Refugee resettlement is the most thorough, cumbersome, multilayered vetting system we have for the admission of anyone to the country.

I hope that the states are taking seriously their obligations to harden the cybersecurity around the election infrastructure that Americans rely upon and need.